Sink your toes into this: Beach sand can be used to make lithium-ion batteries that last three times longer than current models, according to a study published in the journal Scientific Reports.

Made with some breadcrumbs, egg, and 20,000 lab-grown cow muscle cells, the world's first lab-grown burger made its debut last year. It was a proof of concept, evidence that you can make meat in lab. The technology is too difficult and expensive to show up grocery stores any time soon. In the future, however, proponents hope so-called cultured meat will get cheaper. If it does, making beef from stem cells could be an environmentally friendly alternative to, you know, killing animals for food. Raising cattle takes up a lot of arable land and water and creates greenhouse gas emissions. Engineers working on in vitro meat hope their creations will be less harmful on the environment. But will they ever get there?

Scientists around the world have worked on making buildings, cars and light bulbs more environmentally friendly. What's next? Cows.

Yesterday, Amazon announced the new MatchBook service, which offers a deeply discounted Kindle version of a book when you buy a new copy of the physical version. It's something people have been calling for for a while; why not toss in a digital version, which is essentially free to create and distribute? And it's not just new books - if you've ever bought a qualifying book from Amazon, even all the way back in 1995, when the site launched, you can get a digital edition for somewhere between $3 and free.